PORTLAND, Ore. — A snowboarder traveling through an ice tunnel on Oregon's Mount Hood with five companions was buried Saturday when the tunnel collapsed, officials said.

Rescuers quickly responded but halted efforts after dark Saturday night, and said they will resume the search around dawn Sunday.

The other five were uninjured in the collapse Saturday afternoon and called police. They also attempted to dig the man out, but were unable to break through thick snow and ice.

"They tried digging for an hour, but the problem is the stuff is so thick that they couldn't get through it," Hood River Sheriff's Office Sgt. Pete Hughes said. "We're getting chainsaws, if that's any indication."

Early reports from police incorrectly stated there were seven people in the group. The initial reports also referred to an avalanche, but it was not immediately clear if one had occurred.

The man was trapped on the White River Glacier, which begins about 6,000 feet up the south side of the mountain.

"It trapped one person in the tunnel, (but) we're not sure if he was the last one out or it just caught him," Hughes said. "It sounds like there's a significant amount of ice and snow that fell."

An airplane was dispatched to survey the area, along with crews from local sheriff's offices.

Seven rescuers, including five members of an all-volunteer group called the CragRats, were on the mountain on Saturday night.

Hughes said it will "take some doing" to reach the area where the snowboarder was buried. Companions took pictures of the area just before the tunnel collapsed, Hughes said, giving searchers a better idea of where to search.

Warm temperatures made snow on the mountain slushier and more easily sloughed off the surface, adding to the challenge of attempting to reach the snowboarder.